The British and Irish ringing scheme has, for a number of
years, emphasised the conservation value of the species being studied. Ringers
usually pay for their rings, but for some species they are free, and other species attract a rebate for every bird ringed as a recognition
of their special importance. Seed-eating birds of
farmland have been especially hard-hit by agricultural changes during the last
20 or 30 years, and many of them are now designated
species of conservation
concern, most of them on the 'Red
List' because of rapid population declines of more than 50% in 25 years.
Rebates on ring costs are paid for all such species.

Various 'agri-environment' schemes are now available (from
DEFRA, the UK Government's Department for the Environment, Food and Rural
Affairs) to pay farmers to manage their land in ways that are sympathetic to
wildlife, such as leaving uncultivated field margins, creating ponds, leaving
hedges untrimmed for two or three years, and so on. Another of the options in
the Environmental
Stewardship scheme is planting wild bird seed mixtures specifically to
benefit the seed-eating species of conservation concern. Areas of up to 0.5ha
are planted with small-seed bearing crops such as kale, quinoa, linseed or
millet.

We have recently started ringing on one such farm where the
conservation-minded farmer has now
planted four patches of wild bird crops. A line of mist-nets along a hedge readily
catches some of the birds leaving the seed-rich crop, mostly kale in the field shown below:

Yellowhammers Emberiza citrinella apparently prefer
the seeds of quinoa. As commented
previously, this species can be challenging to age and sex. The head
pattern, and tail shape and abrasion, are the main characteristics for ageing
Yellowhammers. The extent of yellow is the main feature used for sexing, as with
the male (at left below) and female (on the right), both first-year birds:

The mantle and rump can be helpful supporting characters, the
male (on the left below) being somewhat brighter and more rusty coloured than
the female (on the right):

An old name for Yellowhammer is the Yellow Bunting, and the
similarity between Yellowhammer and the congeneric Reed Bunting Emberiza
schoeniclus can clearly be seen in this image of two first-year females:

Reed Bunting can be a tricky species to age. Most
first-year birds moult all of their greater coverts and the moult limit is
usually difficult to see. The tail shape is diagnostic, although we have to
beware of those first-year birds that have moulted all of their tail. Classic
first-year (left) and adult (right) rectrices, in birds caught on 29 November 2005, are shown
here:

Note that the tail of the first-year bird is already quite
worn: at this time of year, the degree of feather abrasion can also be quite
a helpful guide for ageing. First-year birds fledged around the beginning of
June, so their flight feathers are now about six months old. Adult birds
underwent a complete moult, finishing between mid-August and the end of
September (see
here for a bird actively moulting on 23
August) and thus adults have all their feathers only about three months old. As
well as being only about half as old, adult-type feathers are physically
stronger than the weak juvenile feathers. The difference in wear can often be
seen. The first-year bird, on the left, has slightly worn primary tips while the
adult bird, on the right, has feathers in pristine condition.

Tree Sparrows Passer montanus also benefit from these
seed crops. Their ageing and sexing present no challenge whatsoever to the
ringer, as they are impossible to age by plumage, adults and first-year birds having a complete moult in the autumn.
There is also no way of distinguishing the sexes outside the breeding season.
Sparrows are often thought of as drab, brown birds - the archetypal 'little
brown job' - but, in the hand, the mixture of shades of colour is quite stunning:

Males, like this bird, have just a hint of red
in the breast during winter. By the breeding season he will have acquired bright red plumage, like the bird shown
here.

Another species that apparently found these seed plots to its
liking was Dunnock Prunella modularis. This is also on the BTO's 'amber
list' of species of conservation concern. It is another difficult species for
ringers to age by plumage: most first-year birds do not show an obvious moult
limit (60% of Jenni & Winkler's sample in Switzerland had moulted none of their
greater coverts - Moult and Ageing of European Passerines, 1994, publ.
Academic Press). The colour of the iris is often diagnostic: as with most
species, the iris tends to become redder with age. However, this
characteristic becomes less useful as the winter progresses and different birds
change towards the 'adult' colour at different rates; also, some adult birds
never seem to acquire a reddish eye. The iris colour of small
passerines can be difficult to photograph, but the two images below, taken on 29
November 2005, show the effect quite well. The top bird is an adult, with a first-year bird (Euring
age 3) below:

Note that the bill colour, mentioned by Svensson
(Identification Guide to European Passerines, 1992) as an ageing characteristic -
'all dark (blackish)' in adults and 'dark brown with slightly paler base to
lower mandible' in most first-years -
does not work for these two individuals, and we have a number of retrapped
adults on other sites, known from their rings to be more than one year old, whose bills also
were not wholly black.

All of the species mentioned above are defined as species
of conservation concern, with Tree Sparrow, Linnet, Yellowhammer and Reed
Bunting all on the Red List. It is only with hindsight that species can be
defined as of conservation concern, because of their drop in population over a
period of time. Twenty-five years ago, few ringers would have believed that we
would now be receiving a rebate on rings used for House Sparrows Passer
domesticus and Starlings Sturnus vulgaris. Although we are now being
financially encouraged to study them, it is historical data that are likely to
be of most use in teasing out the possible causes for population declines. Such
information does exist in the archives of the BTO, and this is one of the
advantages of having a ringing scheme in which ringers can, provided they pay
for the rings used (and are licensed to do so, of course), study whatever they want.

Many of the birds feeding on the wild bird seed crop on this
farm are Chaffinches Fringilla coelebs, a species whose British breeding
population has remained stable throughout the declines experienced by other
seed-eaters. Chaffinches are amongst my favourite
birds, for which I wrote the species text for the BTO's
1981-84 Winter Atlas
and the Migration Atlas. Many of these Chaffinches
are likely to be migrants from Scandinavia, as are the Bramblings Fringilla montifringilla
that accompanied them: maps of Merseyside Ringing Group's overseas recoveries
and controls of these two species can be found
here.

Most photographs of these finches are of the more
spectacularly-coloured males, so these two help to redress the balance, a female
Chaffinch (left) and a female Brambling (right):

Finally, any area with high concentrations of birds will
attract its fair share of predators, Sparrowhawk Accipiter nisus being
the main species that preys on small birds. Several have been seen in the area,
but this female was the only one caught. She was easily identified as a
first-year bird by the brown fringing on all of the feathers of the wing and
mantle, and the pale lemon-yellow iris:

It was not surprising to find female Sparrowhawks in
habitat like this. As with all accipiters, the females are much bigger
than the males, typically twice their weight in the case of Sparrowhawks. The
females tend to hunt in more open areas such as farmland, while the smaller males are usually to be found in woodland.

To finish where we began, British ringers also receive a
rebate on the cost of rings used on all top predators. Ringing at this farm is
rewarding in more ways than one!